The diagrams you see of
the vertical sleeve gastrectomy look like this and patients are told
they will have a "fully functional stomach" only just smaller and from
the diagram it looks like that, doesn't it?

However the reality is a bit different. Here is a photo of a VSG from a
surgeon's site: According to the text on the surgeon's site, the sleeve is the next
best thing since apple pie so he's not against it at all: The
little organ beside the sleeve is the gall bladder so you see, the
sleeve is not very long!

Now, let's take a closer look at the sleeve part:

This part is likely only a couple of inches long! Does that look
like a "fully functional stomach" to you? This surgeon is likely doing a
FOUR oz sleeve which is bigger than a 2 oz sleeve but how big is 2 oz
anyway? The staples up the entire size of the tiny pouch will
likely prevent much muscular action and that is why, soon those muscles
may atrophy. Your stomach was made a certain size probably for a
reason:

The stomach is not simply passive sac for
storing ingested food, but plays a complex role in the processing of nutrients.
Surgical procedures which interfere with the normal operation of the
stomach inevitably cause multiple problems. (Dr Paul Ernsberger,
Associate Professor of Nutrition, Case Western Medical School)

The little pill cup is 1 oz and the bottle minus the white cap, hold 2
oz so you see, your stomach which will look like above and NOT like the
diagram but will be very small (notice my eye glasses in the photo for
comparison) will likely NOT be a fully functional stomach.